I doubt that he is a leveller reborn. I believe that he is simply a man who posseses the knowledge on raising the Myrkridia. Probably some range of a dark necromancer.
The thing is, had Balor survived and won, the way it was supposed to happen; then the Summoner would have come in about the time that Balor's reign was secure, and raised the Myrkridia to help secure the Dark Age. Since Balor died, the Summoner helped Soulblighter. I believe that Soulblighter either knew or guessed the time of the Summoners arrival, and staged his return around that.
Zandervix
